Rotary drum heat exchanger



May 3, 1966 G. KRIKORIAN ROTARY DRUM HEAT EXCHANGER 3 Sheets-Sheet 1Filed April 5, 1963 May 3, 1966 Filed April 5, 1963 e. KRIKORIAN3,248,803

ROTARY DRUM HEAT EXCHANGER 3 Sheets-Sheet 5 United States Patent M3,248,803 ROTARY DRUM HEAT EXCHANGER Garo Krikorian, Worcester, Mass.,assignor to Rice Barton Corporation, Worcester, Mass., a corporation ofMassachusetts Filed Apr. 5, 1963, Ser. No. 270,919 4 Claims. (Cl.34-110) The present invention relates to improvements in rotary drumheat exchangers.

The invention is shown in two alternative forms, in one form as embodiedin a drum-type dryer having a heated outer shell, and in an alternativeform as embodied in a cooling roll having a cool outer shell.

In a preferred form of the invention, a rotary drum dryer is disclosedhaving a drum of large diameter which comprises a shell, 21 supportingrotary hub rotating on a fixed axis, and supporting disc or spokeelements which project outwardly from the hub and provide support forthe drum. The drum is fitted with a heating system which may comprise anetwork of pipes through which a heating medium, preferably steam, iscirculated about an area adjacent the shell surface to maintain adesired temperature of the external surface of the shell. Dryers of thetype referred to are built to operate at high speeds and with a dryingsurface heated to increasingly high temperatures with the result thatdifiiculty has been experienced in providing a strong drum structurewhich will provide adequately for the expansion and contraction of theheated shell portion of the drum and will, at the same time, insure thatthe rapidly rotating shell is at all times adequately supported and heldin a coaxially aligned position with relation to the hub axis.

In an alternative embodiment of the invention, a cool ing roll isdisclosed which comprises two solidly formed end discs, an outer shellwhich is secured at each end to said discs to rotate on a fixed axis,and an inner shell which cooperates with the outer shell for thecirculation of the cooling medium such as water between said shells. Ina structure of this type also, the difierence in the amount of expansionand contraction experienced in the end discs and in the relativelycolder outer shell has presented problems.

It is an object of the invention to provide a novel and improved drumstructure including a series of expansion joints in said structure soconstructed and arranged that they will permit the shell, heated orcooled as the case may be, to expand and to contract freely withrelation to the relatively constant temperature hub and radialsupporting parts of the drum and which will, at the same time, maintainthe shell securely in an exactly centered and longitudinally determinedposition with relation to the hub axis.

A preferred embodiment of the invention comprises a rotary drum heatexchanger having a shell with an external heat exchanging surface, arotary hub, and a plurality of disc headers mounted on the hub forsupporting the shell, said heat exchanger being provided with a seriesof expansion joints connected between each said disc header and saidshell around the periphery of said disc header, each said expansionjoint comprising .a pin and sleeve connection interconnected betweensaid disc header and shell permitting relative movement of theinterconnected portions of said disc header and shell only along a lineradially of said drum axis. The arrangement is such that the portion ofthe shell at the location of each said expansion joint is freelyadjustable only in a radial direction with relation to said hub, whileat the same time that portion of the shell is fixedly securedtangentially with relation to said disc header. The tangential supportprovided at each of a plurality of such locations combines Patented May3, 1966 to maintain said shell in a fixed position coaxially with saidhub.

In order to provide for expansion and contraction of the shellrelatively to the rotary hub longitudinally, only one of the discheaders is rigidly secured to the rotary hub. Any other said disc headeris connected to the rotary hub by means of a series of axial expansionjoints connected between the said disc header and said rotary hub, eachsaid axial expansion joint comprising a sleeve and pin connectioninterconnected between said disc header and said rotary hub permittingrelative movement of the disc header and said rotary hub only along aline parallel to said hub axis.

In the alternative embodiment of the invention shown, the outer shell ofthe cooling drum is supported coaxially with relation to the endsupporting discs by means of radial pins which are secured at theirouter ends directly into the outer shell and are fitted into sleevesockets formed in the peripheral surface of the end discs.

With the above and other objects in view as may hereinafter appear, theseveral features of the invention consist in the devices, combinationsand arrangement of parts hereinafter described and claimed whichtogether with the advantages to be obtained thereby will be readilyunderstood by one skilled in the art from the following descriptiontaken in connection with the accompanying drawings in which:

FIG. 1 is .a view in end elevation of a rotary drum dryer, but with theadjacent disc header removed, illustrating the several features of theinvention;

FIG. 2 is a view in side elevation of the rotary drum dryer shown inFIG. 1;

FIG. 3 is a detail view on a large scale and in section of the lowerportion of the drum shown in FIG. 2;

FIG. 4 is a fragmentary view of the drum in end elevation illustratingone of the fastening devices for securing the drum to the disc header;

FIG. 5 is a detail sectional view taken on a line 55 of FIG. 3illustrating one of the expansion joints; and

FIG. 6 is a view partly in section of a modified form of the inventionas shown in a cooling roll.

Referring to the drawings, the invention is herein disclosed in apreferred form in a rotary drum dryer of the general type having arotary drum 10 of substantial diameter consisting of a sleeve hub 12supported in sleeve bearings, not shown, and a shell 18 which issupported with relation to the hub by means of two perforated discheaders 20, 22. The shell has formed therein adjacent the outsideperipheral surface a series of parallel longitudinally extendingconduits 24. At the ends of the shell there are provided manifolds 26,28 in the form of steel pipes which are bent into a circular form havingthe same diameter as the shell, and abut the two ends of the shell. Themanifolds extend entirely around the drum. Each conduit 24 is tapped atits two ends into the respective manifolds.

Steam is passed through the manifolds 26, 28 and conduits 24 by means ofa steam supply system which comprises a steam inlet junction 30 and alarge diameter pipe 32 fitted within the sleeve hub 12 through whichsteam is introduced into the drum and a condensate outlet junction 34and a small diameter condensate outlet pipe 36 fitted within the inletpipe 32 through which condensate is withdrawn from the drum. The steaminlet pipe 32 and condensate outlet pipe 36 are connected with themanifolds 26, 28 through connecting pipes which form no part of thepresent invention and are therefore not here further referred to.

In accordance with the invention, the supporting structure for the drumshell 18 including the disc headers 20, 22 is constructed and arrangedto provide a drum structure of maximum strength and rigidity while atthe same time permitting to the shell 18 complete freedom to expand andcontract in accordance with the varying thermal conditions. The discheaders 20, 22 which, in the embodiment shown are constructed of heavymaterial, are divided into outwardly disposed rims or ring members 46,48 which are rigidly secured by an axially extending bolt 50 to inwardlyextending flanges 52, 54 formed at the respective ends of the shell 18,and inner core disc members 56, 58 which are mounted respectively on thehub discs 60, 62 which are fixedly mounted on the sleeve hub 12 of thedrum assembly. In the embodiment shown, the core disc members 56, 58 arepositioned in the same transverse planes respectively with the outwardlydisposed rims 46, 48 and are spaced therefrom a sufiicient amount toallow for any relative expansion or contraction thereof. In order toprovide a rigid axially centered support for the shell 18 on the corediscs 56, 58, there are provided at evenly spaced intervals around theperiphery of each disc header twelve identical expansion joints,generally designated at 66 comprising sleeve and pin connectionsinterconnecting said rims 46, 48 and said core disc members 56, 58, eachsaid sleeve and pin connection permitting relative movement of theinterconnected portions of said rim and core disc members only along aline radially of said drum axis. Said expansion joints have the effectof securing the rim 46 or 48 to the associated inner core disc member 56or 58 in such a manner that the engaged portion of the rim is permittedto move freely in a radial in and out direction, but is positivelysecured against transverse movement with relation to the core disc inany direction. Inasmuch as these expansion joints are identical in theirconstruction and mode of operation, only one such joint will bespecifically described in connection with FIGS. 35, inclusive. As shownin these figures, the expansion joint 66 comprises a metal block 68formed with a pin receiving bore and bolted to the core disc member 56adjacent the peripheral edge thereof. A similarly formed block 70 isbolted to the rim 46 radially outwardly from the block 68 and issimilarly formed with a radial pin receiving bore providing a pinreceiving sleeve element in alignment with the bore formed in the block68. A guiding pin 72 extends through both of said bores and is pressfitted and pinned into the bore of the block 68 being, however, slidablyfitted within the sleeve element provided by the block 70 and boretherethrough. With this arrangement, it will readily be appreciated thatthe portion of the shell, controlled by each expansion joint includingthe guiding pin 72, is free to move radially inwardly and outwardly asthe shell contracts or expands, being, however, rigidly secured againstany lateral movement by engagement with the respective guiding pin 72.

In the illustrated construction, provision is made also for expansionand contraction of the shell in an axial direction. Further inaccordance with the invention, expansion joints are provided between thesleeve hub 12 of the drum and one of the core header discs on which theshell 18 is carried. As best shown in FIGS. 1 and 2 of the drawings, theheader core disc 56 is rigidly secured to the hub disc 68 by bolts 76.The header core disc 58, on the other hand, is supported with relationto the hub disc 62 by means of expansion pins 78 which are fitted intoaligned axially extending bores in the disc member 58 slidable on thehub disc 62. The pins 78 will preferably have a press fit with the pinreceiving bore in the hub disc 62 and a sliding fit with the bore in theheader core disc 58 thus providing an axially expandable pin and sleevebearing connection between said hub disc 62 and said slidable headercore disc 58. A substantial number of these pins is provided at spacedintervals around the circumference of the hub disc in order to provide astrong support for the header core disc 58. The arrangement is such thatthe header core disc 58 is free to move axially as dictated by theexpansion or contraction of the shell 18, but, on the other hand, isvery rigidly supported against lateral or turning movement with relationto the sleeve hub 12.

FIG. 6 of the drawings illustrates another embodiment of the inventionin a cooling roll, which comprises a drum having a peripheral surface inthe form of a shell 82 which is continuously cooled by the circulationof a cooling medium in contact with the inner periphery of said shell.The drum 80 comprises generally two headers 84, 86 on which the shell 82is mounted. The header 84 is formed on the end of a pivot shaft 88 whichcarries one end of the cooling roll assembly, the header 86 beingsimilarly formed on the end of a hollow shaft 90 which provides pivotalsupport for the other end of the cooling roll assembly. The cooling rollassembly is also provided with an inner drum 92 having the end portionsthereof narrowly spaced from the headers 84, 86 and the outer peripherythereof narrowly spaced from the inner periphery of the shell 82 so thata space is provided between the inner drum 92 and shell 82 for thecirculation of cooling water. The inner drum 92 is secured at itsleft-hand end to a bearing block 94 rigidly fastened into a bore in theheader 84 by screws 96. At its right-hand end the inner drum 92 isformed with a tubular extension 98 having a sliding fit with a sleevebearing 100 provided in the header 86.

Coolant is introduced into the cooling roll through an inlet pipe 102which extends through the hollow shaft 90 along the rotational axis ofthe cooling roll being supported at its left-hand end as shown in FIG. 6in the bearing block 94 for the end of the inner drum 92. The coolantenters the coolant space provided interiorly of the shell 82 at theleft-hand end of the drum assembly, flows to the right-hand end of thedrum assembly and is drawn off through a passageway formed between theoutside diameter of the pipe 102 and inside diameter of the hollow shaft90.

In accordance with the invention the shell 82 is fitted over theperipheral faces of the two headers 84, 86 loosely to permit expansionand contraction of the rim with respect to the two headers, beingconnected thereto only by means of radial pins 104 which are arranged intwo rows in staggered relation at spaced intervals about the peripheryof the shell adjacent each end thereof. Each pin 104 is press fittedthrough the shell and extends radially inwardly into and has a slidingfit with a socket 106 which is held by a press fit in a radial bore inthe periphery of the respective header. In the construction shown, thereare twelve pairs of pins 104 mounted at equally spaced intervals aboutthe periphery of the shell 82. The pins are further arranged in opposedrelation at opposite sides of the shell on diameters angularly arrangedwith relation to one another and passing through the axis of theheaders. It will be evident that each opposed pair of pins will providea fixed support for the shell, including the rotational axis thereof,against movement in a direction transversely of the said diameter onwhich said pins are located while permitting expansion and contractionof the shell longitudinally of said diameter, so that the rotationalaxis of the shell is rigidly held at the point of intersection of all ofsaid diameters in a position concentric with the hub axis. Thearrangement is such that the shell 82 is at all times supported securelyin an exactly centered position with relation to the rotational axis ofthe pivot shaft 88 and shaft 90 while at the same time it is permittedto expand and to contract freely in a radial direction independently ofthe headers 84, 86. In order to prevent leakage of the cooling mediumthrough the relatively loose connections provided between the shell 82and the headers 84, 86, the header 86 is provided adjacent its outeredge with a ring 108 which overlies the end of the shell 82. The header84 is similarly provided with a ring 110 which overlies the opposite endof the shell 82. O-rings 112, 114 mounted in the inner faces of therings 108, 110, respectively, prevent the escape of coolant past theends of the outer shell 82. The shell 82 and headers 84, 86 of thecooling roll illustrated in FIG. 6 may be assembled as follows:

The sockets 106 are press fitted into bores in the peripheries of thetwo headers 84, 86 and the shell 82, similarly drilled to receive thepins 104, is then slid into position axially over the headers 84, 86.Each pin receiving hole in the shell 82 is now lined up with theassociated socket 106, and a pin 104 is driven into position through theshell 82. Finally the rings 110, 108 are assembled and screwed to theouter faces of the headers 84, 86 in the positions shown.

With the construction shown, the outer shell 82 is permitted to expandand to contract radially with relation to the relatively thick-walledheaders 84, 86 by means of the pin and socket connections abovedescribed, while at the same time the shell is at all times held firmlyin its centered position with relation to the rotational axis of thecooling roll. Expansion and contraction of the outer shell 82 axiallywith relation to the inner drum 92 is permitted by the sliding fitprovided between the bearing 100 formed within the right-hand header 84and the tubular extension 98 of the drum 92.

The invention having been described what is claimed is:

1. A rotary drum for use in a rotary drum heat exchanger which comprisesa shell having an external heat exchanging surface, a rotary hub, aplurality of disc headers mounted on the hub and spaced from one anotheralong the length of the shell for supporting said shell, a series ofexpansion joints on which the shell is supported from said disc headerscomprising opposed pairs of pin and sleeve bearing connections atopposite sides of each disc header along diameters intersecting the hubaxis at a substantial angle to one another, the pins extending radiallyof the drum axis for movement relatively to said sleeve bearings onlyalong said diameter, each opposed pair of pin and sleeve bearingconnections on a said diameter providing a fixed support for said shellincluding the rotational axis thereof against movement in a directiontransversely of said diameter, while permitting expansion andcontraction of the shell longitudinally of said diameter, whereby therotational axis of the shell is rigidly held at the intersection of saiddiameters concentric with the hub axis.

2. A rotary drum according to claim 1 in which each said expansion jointcomprises a guide block having a bore extending radially of the shellaxis secured to said shell, a guide block having a bore extending alongthe same radial line secured to said disc header, a guide pin extendingthrough both of said bores, and means securing said guide pin within oneof said bores in position for sliding engagement with the other saidbore.

3. A rotary drum according to claim 1 in which a plurality of pin andsleeve bearing expansion joints are provided between each said discheader and said shell evenly spaced from one another about the peripheryof said rotary drum and are paired in opposed relation at opposite endsof a plurality of pairs of perpendicularly crossing diameters.

4. A rotary drum according to claim 1 including a said disc headershiftable axially on said hub in accordance with the axial contractionand expansion of said shell, said axially shiftable header comprising ashell supporting disc member having radial pin and sleeve bearingexpansion joints with said shell, a hub disc member fixed to said hub inradially overlapping relation to said shell supporting disc member, anda plurality of axially extending pin and sleeve bearing connectionsbetween the overlapping portions of said hub disc member and said shellsupporting disc member spaced about the axis of said hub on which thesaid shell supporting disc member is keyed to turn with and is freelyshiftable axially with relation to said hub disc member and hub.

References Cited by the Examiner UNITED STATES PATENTS 1,692,537 11/1928Baumann.

1,692,538 11/1928 Baumann 253--69 1,873,743 8/ 1932 Doran.

2,563,692 8/1951 Ostertag 34-124 X 2,622,843 12/ 1952 Williams.

2,628,433 2/ 1953 Ostertag 34-124 2,817,908 12/ 1957 Hornbostel 341 103,060,592 10/1962 Ostertag 34124 3,169,050 2/1965 Kroon 34124 FOREIGNPATENTS 531,605 8/1931 Germany.

WILLIAM F. ODEA, Primary Examiner.

NORMAN YUDKOFF, Examiner.

J. SOFER, Assistant Examiner.

1. A ROTARY DRUM FOR USE IN A ROTARY DRUM HEAT EXCHANGER WHICH COMPRISESA SHELL HAVING AN EXTERNAL HEAT EXCHANGING SURFACE, A ROTARY HUB, APLURALITY OF DISC HEADERS MOUNTED ON THE HUB AND SPACED FROM ONE ANOTHERALONG THE LENGTH OF THE SHELL FOR SUPPORTING SAID SHELL, A SERIES OFEXPANSION JOINTS ON WHICH THE SHELL IS SUPPORTED FROM SAID DISC HEADERSCOMPRISING OPPOSED PAIRS OF PIN AND SLEEVE BEARING CONNECTIONS ATOPPOSITE SIDES OF EACH DISC HEADER ALONG DIAMETERS INTERSECTING THE HUBAXIS AT A SUBSTANTIAL ANGLE TO ONE ANOTHER, THE PINS EXTENDING RADIALLYOF THE DRUM AXIS FOR MOVEMENT RELATIVELY TO SAID SLEEVE BEARINGS ONLYALONG SAID DIAMETER, EACH OPPOSED PAIR OF PIN AND SLEEVE BEARINGCONNECTIONS ON A SAID DIAMETER PROVIDING A FIXED SUPPORT FOR SAID SHELLINCLUDING THE ROTATIONAL AXIS THEREOF AGAINST MOVEMENT IN A DIRECTIONTRANSVERSELY OF SAID DIAMETER, WHILE PERMITTING EXPANSION ANDCONTRACTION OF THE SHELL LONGITUDINALLY OF SAID DIAMETER, WHEREBY THEROTATIONAL AXIS OF THE SHELL IS RIGIDLY HELD AT THE INTERSECTION OF SAIDDIAMETERS CONCENTRIC WITH THE HUB AXIS.